A basic setup involves a wooden pole, a copper spiral winding upward, and a grounding spike or buried wire

https://www.scribd.com/document/1026628805/Electroculture-How-to-Measure-Plant-Response-to-Electricity-201386

A basic setup involves a wooden pole, a copper spiral winding upward, and a grounding spike or buried wire, positioned near crops to capture atmospheric ions and gently influence local electrostatic conditions.